Characterization of high-dimensional entangled systems via mutually unbiased measurements

Area of Science:

• Quantum Information Science
• Quantum Optics
• Quantum State Tomography

Background:

• Mutually unbiased bases (MUBs) are crucial for quantum information protocols like quantum key distribution.
• Defining and measuring MUBs in high-dimensional quantum systems is theoretically and experimentally challenging.

Purpose of the Study:

• To develop an efficient method for quantum state reconstruction in high-dimensional multipartite systems.
• To simplify the process by utilizing MUBs of individual subsystems instead of the entire system.

Main Methods:

• Experimental implementation of quantum state reconstruction using MUBs of subsystems.
• Utilizing photons entangled in orbital angular momentum (OAM) as the high-dimensional system.
• Performing measurements for dimensions ranging from d=2 to d=5.

Main Results:

• Demonstrated efficient quantum state reconstruction by focusing on MUBs of individual subsystems.
• Showcased the advantage of using smaller Hilbert spaces for MUB definition and measurement.
• Successfully reconstructed the quantum state of a two-photon OAM entangled system.

Conclusions:

• The proposed method offers a practical approach to quantum state reconstruction in complex, high-dimensional systems.
• This technique simplifies experiments where MUBs for the composite system are difficult to define or measure.
• The findings have implications for advancing quantum information processing and quantum communication.